With the increase in computing power experienced over the last decade, it is now common for individuals and businesses to possess computers capable of performing a wide range of data collection and analysis. Owners of such computers can capture this computing power by coupling many different devices to the computer. This is especially the case with medical diagnostic equipment. Using an available computer, doctors, nurses and support staff can economically collect and tabulate a multitude of different types of medical information, limited only by the different devices which can be interfaced with the computer. For example, when a patient's pulse is desired, a pulse oximeter may be fitted to the patient and the data it collects sent to the computer for translation and processing. Additionally, depending on the computing power available, it may also be possible to simultaneously collect and manipulate other data, such as a patient's blood oxygen content, respiration rate or body temperature, with a variety of other devices, each having a uniquely configured plug corresponding to a uniquely configured socket disposed on the computer. The coupling and decoupling of these devices to the computer exacts a large commitment of time and effort from users who must painstakingly match plugs with corresponding sockets. This situation is exacerbated when a patient's condition changes and new devices must quickly be coupled to the computer, or when a new patient is added to the computer and a new array of devices must be quickly coupled to the computer.
Several options currently exist to help medical staff quickly couple and decouple devices to a computer. One such option is shown in FIG. 1, which gives an isometric view of a plug 100 according to the prior art. As shown in FIG. 1, the plug 100 has a plurality of metal pins 110 protruding from a flat inner base 112 disposed in a protected inner space 115 formed by a protective hood 117. Different devices have different plug configurations with different numbers and placement of pins 110 depending on the types and number of control and data signals required to be transmitted between the device and the computer. The different pin configurations of the various plugs 100 necessitate the inclusion of various sockets (not shown) located on the computer, or alternatively, on an end of a connecting cable with corresponding configurations of pin receivers to receive the various plugs 100. Once a plug 100, and thus its corresponding device, is coupled to a compatible socket, control and data signals from the device are transmitted over insulated wires inside of a cord 120 to respective pins 110. To protect against voltage spikes, electromagnetic interference (EMI), radio frequency interference (RFI) and transient voltages, a ferrite or capacitor structure 122 is placed in the cord 120.
FIG. 1 also illustrates a negative keyway 125 with a width 133 extending through the thickness 135 of the protective hood 117 from the flat inner base 112 to an outer end 130 of the protective hood 117. This negative keyway 125 can be used to prevent a socket from being used with an ill-suited plug. For example, in order to create a socket which will only mate with the plug 100 shown in FIG. 1, the socket should include a protruding positive keyway with a length less than or equal to the length of the negative keyway 125, as measured from the outer end 130 of the protective hood to the flat inner base 112, and a width less than or equal to the width 133 of the keyway 125. If the positive keyway on the socket is too long or too wide, it will obstruct the mating of the socket with the plug 100. Additionally, the positive keyway on the socket must be accurately placed to mate with the negative keyway 125 when the plug 100 mates with the socket. If this does not occur, even positive keyways with proper widths and lengths will obscure the mating of the socket to the plug 100, and the pins 110 of the plug 100 will not contact the pin receivers of the socket.
The negative keyway 125 has a large shortcoming, however, in that it is of no value in preventing the cross connection of plugs unless it is used in conjunction with sockets having positive keyways. For example, in the description given above, if the socket has no positive keyway it will mate with the plug 100 regardless of the size and location of the negative keyway 125 present on the plug 100.
Another method in which a socket can be readily indicated as compatible with a certain plug is through color coding. Using such a method, compatible plugs and sockets are created to be the same color, enabling users to quickly and easily couple plugs to corresponding sockets by matching their colors. This system is not fail-safe however, and it can be rendered useless by low light situations and scenarios in which users are unable to physically see both the plug and socket (such as when the socket is backed up against a wall adjacent to the computer, or the socket is in a hard to see location).
Still looking at FIG. 1, once the plug 100 is mated with an appropriate socket, the plug 100 is held in place by friction between the pins 110 and the corresponding pin receivers in the socket, as well as by friction between the other areas of the socket which contact the plug 100. The cumulative friction between these areas is often quite low, making it correspondingly easy for the plug 100 to be accidentally disengaged from the socket or to slip out of the socket due to factors such as the weight of the cord 120 hanging from the plug 100, or incidental contact between the plug 100 and objects brushing against it, which is a common occurrence in a busy medical atmosphere. Such slippage only needs to proceed far enough to pull the pins 110 away from their pin receivers to result in a failure of the connection.
A prior art improvement over plug 100 will now be discussed by referring to FIGS. 2a–b. FIG. 2a gives a top view of a plug 200 similar to plug 100, but with cantilever latches 210 disposed on its outer sides 220 at a centerline of the thickness of the plug 200. The precise function of these latches 210 is illustrated in FIG. 2b, which provides a cutaway view of an inside portion 221 of the socket engaged with one of the latches 210. According to the design of these latches 210, as the plug 200 is placed into contact and mated with a suitable socket, the pawls 230 disposed on the end of each latch 210 contact a catching device 222 located in the socket. As the plug 200 is advanced into the socket in direction 233, a sloping front surface 235 of the pawl 230 contacts a sloping receiving surface 237 of the catching device 222 and the force created by this contact initiates a bending of the latch 210 into a free space 238 (FIG. 2a) between the latch body 250 (also shown in FIG. 2a) and the body 239 of the plug 200.
Again referring to FIG. 2b as well as FIG. 2a, when the pawl 230 reaches the end of the sloping receiving surface 237 a vertical face 240 is encountered, at which point the latch 210 snaps out of free space 238 away from the plug body 239 and toward the inside portion 221 of the socket. The pawl 230 is then snared by the vertical face 240 which contacts a rear vertical surface 242 of the pawl 230, preventing the latch 210, and thus the entire plug 200, from moving in a direction opposite to direction 233 and decoupling from the socket.
When coupled, a portion of the plug body 239 extends out of the socket to an extent that sections of the latches 210 are readily accessible to the user. Additionally, as the latch pawl 230 couples with the catching device 222, the latch 210 snaps out of the free space 238 creating both an audible report and a vibratory indication to the user that the plug 200 has become coupled to the socket.
In order to reverse this process and release the latch 210 from the catching device 222, the user squeezes the accessible portions of the latches 210 toward the plug body 239. This moves the pawls 230 relative to the plug body 239, displacing them into the free space 238. When enough force is applied by the user, the rear vertical surfaces 242 of the pawls 230 clear the vertical faces 240 of the catching devices 222, and the plug 200 may be moved in a direction opposite to direction 233 and be decoupled from the socket.
Latches 210 are somewhat difficult to use however, since their cantilever configuration leaves them especially susceptible to entanglement with objects or wires small enough to fit into the free space 238. Additionally, the shape of the pawl 230 itself encourages snagging and entanglement with a wide variety of different materials. Such snagging problems can result in damage to the objects which become entangled, as well as deformation or destruction of the latches 210 themselves.
Accordingly, there is a need in the art for a plug with a robust latching mechanism that resists snags. Moreover, there is a need in the art for a socket connector in which a variety of plugs may be quickly and easily coupled to proper corresponding sockets by a user.